Means for counterbalancing the acceleration forces in rapidly oscillating machine members especially doffer combs



FER COMBS 2 Sheets-Sheet 1 ON FORCES IN RAPIDLY AGCELERATI OSCILLAIINGMACHINE MEMBERS ESPECIALLY DOF Filed April 25, 1967 Oct. 1969 J. A.LILJA ETAL MEANS FOR COUNTERBALANCING THE ATTYS.

1969 J. A. LILJA ETAL 3, 7

. MEANS FOR COUNTERBALANCING THE ACCELERATION FORCES IN RAPIDLYOSCILLATING MACHINE MEMBERS ESPECIALLY DOFFER COMBS Filed April 25, 19672 Sheets-Sheet 2 M5 M4 M0 J4 242 g @245 A\\\ W 6 4 [45 24. Z40

INVENTORSZ JOHN ALLAN LILJA AKE ESKIL LJUNGHOLM AT YS.

United States Patent Int. Cl. D01g /46 US. Cl. 19-406 1 Claim ABSTRACTOF THE DISCLOSURE A means for counterbalancing acceleration forces inrapidly oscillating machine members, for example, the accelerationforces in the oscillating comb of a doffer comb consisting of anelongated torsion bar secured at one end to a fixed support and fixedlyconnected at its opposite end to a shaft extension of a rock shaft in adoffer comb box. The torsion rod extends through an elongated bore inthe dofier comb shaft being spaced therefrom and located on an axiseccentric from the axis of the doffer comb shaft.

This is a continuation-in-part application of our prior application Ser.No. 422,336, filed Dec. 30, 1964, now abandoned, for Means forCounterbalancing the Acceleration Forces in Rapidly Oscillating MachineMembers, Especially Doffer Combs.

The present invention relates to improvements in mechanisms which havean oscillating member and more particularly to a means forcounterbalancing acceleration forces in rapidly oscillating machinemembers. The present invention has particular application in the textileindustry for use in carding apparatus. These carding apparatus generallyinclude a doffer comb box having a crank mechanism which transforms therotating motion of a crank shaft driven by the cylinder of the card toan oscillating motion of a rock shaft which in turn is connected to thedoifer comb.

The deflection of the rocking shaft for a typical dofler comb box is110. Accordingly when the crank shaft is rotated, the doifer comboscillates with fixed turning points, the length of the stroke beingconstant and independent of the speed and being generally referred to asa guided motion type. The rocking and crank shafts are mounted inbearings and it has been found that the operating speed of the doffercomb assembly must be maintained below a predetermined level for examplerotation of the crank shaft below 1800 r.p.m., in order for the bearingto have an acceptable life, for example 40,000 to 50,000 operatinghours. It has been found that for high production cards it is necessaryto operate the machine at substantially higher speeds and it has beenfound that moderate increases in speed resulted in acceleration forceswhich were so considerable that the doffer comb box bearings failedafter a relatively short time. For example, when the speed of the crankshaft is increased, the bearing load will increase in proportion to thesquare on the speed rise and thus, when speed is increased for instance11%, the bearing Working life will be reduced by half. Since it isdesirable to drive the dotfer comb in high production cards atfrequencies of about 3,000 strokes per minute or eventually even higher,it is obvious that the bearing life will be very short. Moreover, at theelevated speeds, vibrations in the doffer comb results in unsatisfactoryweb removal.

Accordingly, an essential requirement in cards used on high productionmachines is the accommodation of the considerable acceleration forcesand the present invention provides a novel and comparatively simplifiedmeans for achieving this end.

To this end, according to the present invention there is provided for amechanism having a member which oscillates when the member is in use, aspring member connected at one end to the oscillating member and heldfixed at its other end, which spring is so dimensioned and connected insuch a manner that the oscillation of the member causes a spring load tobe applied to the oscillating member or such drive in opposition to theacceleration and retardation loads so that the net reaction on thebearings of the drive is reduced as compared with the same mechanismhaving no springs. More particularly, in accordance with a preferredform of the invention as it applies to a dolfer comb box, there isprovided a torsion bar, one end of which is held fixed and the other endis connected to the crank shaft which drives the shaft extension whichin turn mounts the doifer comb to oscillate therewith, the torsion barbeing so dimensioned that the spring load which applies to the shaftopposes the acceleration and retardation loads of the doifer comb to anextent that the reaction load on the bearings of the shaft are reducedas compared with a doifer comb box of the same design but having notorsion bar.

It is noted that in the preferred form of the invention, the torsion barextends through an elongated bore in the dofier comb shaft being spacedtherefrom and located on an axis eccentric from the axis of rotation ofthe doffer comb shaft. It is by this arrangement that it is possible toachieve the desired reduction of harmful effect on the bearings mountingthe crank shaft and rocking shaft in the dofier comb box. For example,with the arrangement of the present invention, it has been found thateven at speeds of 3,000 r.p.m., the forces on the bearing are reduced toa point whereby the bearing life is increased 20 to 30 times andproviding an acceptable working life of about 30,000 to 40,000 hours.

These and other objects of the present invention and the variousfeatures and details of the operation and construction thereof arehereinafter more fully set forth with reference to the accompanyingdrawings, wherein:

FIG. 1 is a transverse sectional view showing a dofier comb box anddofier comb assembly including the preferred embodiment of the presentinvention;

FIG. 2 is a sectional view taken on line 22 of FIG. 1;

FIG. 2a is a sectional view taken on line 2a2a of FIG. 1;

FIGS. 3 and 4 are charts showing reduction in the acceleration forces inan assembly of the type shown in FIG. 1 embodying the present invention;

FIG. 5 is a view partly in section showing a second embodiment of springbiasing means in accordance with the present invention for a dofier combassembly;

FIG. 6 is a view taken on lines 6-6 of FIG. 5;

FIG. 7 is an alternate embodiment of biasing means similar in somerespects to the embodiments shown in FIGS. 5 and 6; and

FIG. 8 is a view partly in section showing a fourth embodiment inaccordance with the present invention.

Referring now to the drawing and particularly to FIG. 1 thereof, thereis illustrated a dofier comb assembly incorporating the presentinvention. The assembly includes a dotfer comb box generally designatedby the numeral 10 which houses a rotatably mounted crank shaft 12 whichin turn mounts at its inner end a pulley 14 which is driven by a belttransmission connected to the cylinder of a card (not shown). The crankshaft as illustrated is journalled in bearing assemblies 16 and 18 andmounts at its forward end an eccentric crank 20 which is rotatablyjournalled in a. connecting arm 22, the connecting arm being suitablypivotally connected to an arm 24 formed integrally with a shaftextension 26 of a rock shaft 28 journalled in bearings 29 and 31 in thedoffer comb box 10.

The doffer comb assembly, generally designated by the numeral includes adofier comb shaft 32 having reduced terminal end portions 34 and 36 anda plurality of supporting arms 38 at spaced apart points along thelength of the shaft 32 which mount the dotfer comb 40. The innerterminal end portion 34 of the dofier comb assembly 30 is connected tothe shaft extension 26 of the dotfer comb box, and to this end, theshaft extension 26 is provided with a bore 42 which receives the innerterminal end portion 34 of the doffer comb shaft, the comb terminal endportion being held in place by means of a compression sleeve 44 having aconical bore adapted to exert a clamping force on the projectingterminal end portion 34 of the comb shaft 32 and a nut 45. The oppositeterminal end portion 36 of the doifer comb shaft is mounted foroscillatory movement in a fixed support 48 by means of a self-aligningball bearing 50 seated on an adapter sleeve 46. By this arrangement inthe normal operation of the doffer comb assembly, the comb 40 isoscillated back and forth due to the driving connections between therocking shaft, the crank 20, crank shaft and pulley which, as notedabove, is connected to the cylinder of the card.

In accordance with the present invention means are provided forcounterbalancing the acceleration forces which contribute to bearingfailure and more specifically a means for conserving the energy of thedotfer comb at the reversing position and reapplying it to the comb byway of additional impetus when the comb is accelerated toward the middleposition. By this arrangement the high acceleration forces associatedwith reversal at the end positions are reduced and hence the life of thebearings in the dolfer comb box can be increased considerably from 20 to30 times depending on the working speed. To this end in accordance withthe principal embodiment of the invention illustrated in FIG. 1, atorsion rod 60 is provided which, as illustrated, extends through and isspaced from the peripheral wall of an eccentric bore 62 in the doffercomb shaft 32 and is secured at its inner end in a bore of the rockshaft by means of a press fit, and at the opposite end is fixedlysecured to the support 48 by means, in the present instance of a nut 63and a compression sleeve 64.

To obtain a balanced construction it may also be of advantage to locatethe ends of the comb shaft eccentrically on the comb shaft whereby it ispossible to balance the doffer comb without the necessity of applyingweights, etc. externally of the comb shaft.

In the operation of apparatus of this type it may be necessary to varythe speed of oscillation of the doifer comb and this may be accomplishedthrough the transmission connection to the dofier comb box. For example,it may be desirable to change the speed for treatment of differentfibrous materials or producing different output volumes per hour. Inapparatus embodying the torsion rod of the present invention, at thestart of the card, the doflfer cylinder and the dotfer comb will have aproportional relation between surface speed and frequency respectivelyfrom the start enduring all of the acceleration during maximum speed andthen during steady state. The torsion rod of the present inventionoperates to balance the acceleration forces under all of theseconditions. For example, the chart in FIG. 3 shows that as the speed isincreased from N1 to N3, the load increases at all positions of thedoifer comb. FIG. 4 shows how the forces are reduced by means of thepresent invention. Curve K1 corresponds to curve N3 in FIG. 3 and curveK2 represents the counter-acting force of the torsion rod. The resultingforce may be read on curve K and as is clear, there is a considerablebearing load decrease by reason of the operation of the torsion rod inaccordance with the present invention.

The particular arrangement of the torsion rod produces the desiredresults noted above and it is noted that these results cannot beachieved in systems which bear a superficial resemblance to the presentinvention.

For example, in a system where the torsion rod carries a mass at bothends, if one mass is held fixed and the other is given a revolvingmovement, the masses Will oscillate in opposite directions back andforth when set free. The extent of oscillation depends on size of themasses and the rheostat in the torsion rod. In an arrangement of thistype, the forces are not counter-balanced under all operating conditionsof the dofier comb assembly.

There is shown in FIGS. 5 and 6 a doifer comb assembly incorporatinganother embodiment of means for reducing the high acceleration forces atthe end positions of the doifer comb. In this embodiment the generalarrangement of the dolfer comb box and doffer comb are similar to thatdescribed above and comprise a dolfer comb box having rotatablyjournalled therein a crank shaft 82 mounting at one end a pulley whichis driven by a belt transmission connected by a cylinder of the card anda rock shaft 84 connected to the crank shaft by means of a crankmechanism generally designated by the numeral 86 to effect oscillatingmovement of the rock shaft and the doffer comb 90 connected thereto. Thedoifer comb 90 as illustrated is connected at one end to the rock shaftextension 84a by means of a sleeve 132 and a nut 134 and at its oppositeend is rotatably journalled in a hearing assembly housed in a fixedsupport.

In the present instance, the outer end of the rock shaft 84 has anextension which carries a sleeve having a pair of diametrically opposedoutwardly extending rigid wing members 142. The outer ends of the wingmembers engage between opposing coil springs 144, the coil springs asillustrated being fixed between stationary ear extensions formedintegrally with the doifer comb box.

An alternate spring arrangement similar to the embodiment describedabove is illustrated in FIG. 7. The dofrer comb box and comb assemblyare identical to that described in connection with the embodiment ofFIG. 6. However, in the present instance a collar 240 is mounted on theouter extension of the rock shaft which in turn mounts a pair ofdiametrically opposed resilient wings 242 which, at their outer endsengage opposed restraining members 243. By this arrangement, duringoscillation of the rock shaft, the leaves 242 yield and the effect is toreduce the moment at the reversing position of the comb shaft which hasthe effect of minimizing the deleterious forces on the bearings in thedoffer comb box mounting the various actuating elements thereof.

There is illustrated in FIG. 8 still another embodiment in accordancewith the present invention. The doffer comb box and dolfer comb shaftassembly are generally similar to the previously described embodiments,the dofler comb box which is generally designated by the numeral housinga rotatably mounted crank shaft which carried a pulley 314 at one enddriven by a belt transmission connected to the cylinder of a card, acrank shaft journalled in bearing assemblies in the doffer comb box anda crank mechanism connecting the crank shaft to a rock shaft 328. Therock shaft 328 has a forward extension 328a having a bore therein whichreceives the inner terminal end portion of the doffer comb shaft 332,the opposite end of the dolfer comb shaft 332 having a terminal portionwhich is rotatably journalled in bearing mounted in a fixed support.

In the present instance the rock shaft has an axially extending bore 359therein running throughout its length which communicates with the boresection in which the inner terminal end of the dotfer comb shaft ismounted to receive a torsion bar 360. The torsion bar at one end isfixedly connected to the main frame of the machine as at 365 and at itsopposite end has an enlarged piston portion 361 which is press fitted inthe bore in the rock shaft. The portion of the torsion bar 360 whichtelescopes in the bore 359 of rock shaft 328 is spaced therefrom.Accordingly, in operation as the rock shaft oscillates to impart anoscillating movement to the doffer comb assembly between opposite limitpositions, the torsion bar is twisted slightly with the effect that itreduces the moment at the extreme limit positions at the doifer combassembly which in turn reduces the harmful forces on the bearingsmounting the various elements of the doifer comb box to extend theirlife and the life of the entire assembly considerably.

While particular embodiments of the present invention have beenillustrated and described herein, it is not intended to limit theinvention and changes and modifications may be made within the scope ofthe following claim.

We claim:

1. A dofling mechanism comprising a doffer comb box, a dofifer combshaft, a comb mounted on said shaft, a rock shaft rotatably journalledin bearings in said doffer comb box and connected to the dofter combshaft, actuating means in said doffer comb box for oscillating the rockshaft and doffer comb shaft and biasing means operable to provide a loadon the doifer comb shaft opposing the acceleration and retardation loadswhereby the net reaction on the bearings is reduced, said biasing meanscomprising a pair of diametrically opposed resilient wing membersprojecting radially from one end of said rock shaft and opposedrestraining members engaging the outer terminal ends of each of saidwing members.

References Cited UNITED STATES PATENTS 2,604,669 7/1952 Smith 19-1062,827,578 3/1958 Carissimi et al 31038 FOREIGN PATENTS 1,351,572 12/1963France.

841,869 6/ 1952 Germany. 744,786 2/ 1956 Great Britain. 477,650 l/ 1953Italy.

DORSEY NEWTON, Primary Examiner

